Noise at freeway speed

[metalwhiz]

Pretty sure that tube assembly will be closer to $20 and not $5 as some have mentioned before. I just bought one off Ebay for $17. Still worth it for peace of mind.

 

[Mike Serra]

I've developed an occasional sound that sounds like a can rattling around at freeway speeds coming from front of truck. It comes and goes and I haven't been able to reproduce it on demand but was able to get a video/sound clip. You can see in the video the turbo isn't kicking in, speed is constant, but comes on randomly. Any ideas?

I know what this is as it happened to me also on my 17. It was a vacuum sensor in the AWD in one of your front wheels. Took it to the dealer, of course they had to order the sensor, took about a week.

 

[Maxcap]

The part and labor was warrantied.... the service mgr said it was a $5 part that could have caused thousands in damage. Not sure that $5 or $20 makes much of a difference, when it's easily changed out. Just my .02 (pun intended).

 

[Lags]

It’s the IWE check valve in the engine compartment. Top right close to the firewall on the other side of the intake.

It is part of the vacuum system for the hubs. Your truck is trying to engage 4WD. The lines are always under vacuum pressure, when you switch to 4H or 4L the pressure is released and the hubs engage. In your case there is a leak and the the pressure escaping and the hubs try to engage.

 

[costnsg]

I agree with the others. It's almost certainly that silly little check valve. Ford has a service bulletin out on this problem. Unfortunately it's way too common. As already mentioned, if you shift to 4A it releases the vacuum from the IWE's, engaging the front hubs. Now the noise will probably stop (if it's the check valve as suspected), but you'll be running with the front drive train turning with the wheel hubs until you get the check valve replaced and shift back to 2WD.